1. Field
Embodiments relate to a backlight unit.
2. Description of the Related Art
A light emitting diode (LED) is a device that converts an electrical signal into light using the properties of a compound semiconductor. The LED is used in electric home appliances, remote controllers, electric bulletin boards, displays, various kinds of automated equipment, etc. The application range of LEDs continues to expand.
A backlight unit, to which light emitting diodes are applied, may be used in a display apparatus, such as a liquid crystal display apparatus, and lighting apparatuses for various other fields. Generally, the backlight unit may include a light emitting device package including a light emitting diode, a light guide plate to diffuse light emitted from the light emitting device package, and an optical sheet to diffuse or condense light emitted from the light guide plate.
The light emitting diode included in the light emitting device package of the backlight unit may be driven at low voltage with high efficiency. The light emitting diode is a two-terminal diode device including a compound semiconductor, such as gallium arsenide (GaAs), gallium nitride (GaN) or indium gallium nitride (InGaN). When power is applied to a cathode terminal and an anode terminal of the light emitting diode, the light emitting diode emits light energy generated during recombination between electrons and holes in the form of visible light.
Based on the position of the light emitting device package, the backlight unit is classified as an edge type backlight unit or a direct type backlight unit.
The edge type backlight unit is generally used in relatively small-sized liquid crystal display apparatuses, such as monitors for laptop computers and desktop computers. The edge type backlight unit has the effect of high light uniformity, long lifespan, and reducing the thickness of the liquid crystal display apparatuses.
In recent years, research has been carried out on a backlight unit configured to have not only an edge type structure but also a direct type structure.